Brake mechanism



20, 1940. c. D. sTEWART 2,211,915

BRAK MEcHANISM F11ed Feb. 18. 1939 3 sheetssheet 3 INVENToR CARLToN D STEWART ATToRNEY detaned shoWing of an of the paftB theroof fs deemed unnecessary.

'Ihe bfake shoes lf at each end of eooh vvf1ee1 and B-xle aSSefnbly afe offanged one on each sfde of a veftfoally dispoSed hanger levef 22 and ofe pfvotany connected to the levef by fnenS of a transversely extending pin 29. The upper end of thfs levef fS pivotol1y oonnected to the outer ond poftfon of the bfoko oofffer l2 by fneans of a pin fo.

I f1o 1oWef endS of the bfake cylfnder levef 2 and the hangef leve1' 22 afe opefotfvely con neoted together by Ineans of 1ongftudinany ex tending connectof Whfch, fn the present em bodifnent of the fnventfon, oofnprises 9. fod fl Which fs operatively connected of one end fo the hongef lever 32 and of fts othef end .to the oylindef 32 thfough the fflediofn of the slook ad justef 22 ooffied by the fod The slaok adJuster 22 In y be of any oonventfona1 type having s fnovoble cfoss he d 22 vvhioh is opefatively connected to the ovef end of the bfake oyHndef lever ond Whfoh fnay be o tuated by 8 sofew fnechaniSm odopted fo be fnanuaHy opefated thfough the Inedfun of an adjusting nut f5.

s hefeinbefore fnentioned the brake dfufns l2 afe made integro1 With ealoh othef and the bfaking suTfaces thereof are sepofated in a df feotfon longitudinally of the axle by a oifoular gfoove 26 Which is of Sumoient Width ond depth to accofnn1odate the connectof fl Which extonds fnto the plane of the dfun1.

Tffe upper end poftfon of each bfake oy11nder levef 3u extendS thfough od veftfoollly exfendfng opening 8 foffned in the bfoke coffier ls, and 8bove the fnefnbef haS a hond bfake pun fod of chain 29 opefatlvely oonneoted thefeto, Which pun Tod of chBin is adapted to be actuBted thfough the fnediun1 of the usua1 fnanuany operoble bfoke fnast.

Wfth the brake cylinder device 2G devoid of ffllld undef pfessure the sevefal pafts of the brake ffggfng vvin be in felease positfon as Shovvn and wnl be maintained in thfS positfon by fhe fofce of gravfty of by al feleaSe spring vvhen s11ch a spfing is emp1oyed.

It Wi11 here be noted that since the journol beofing 6 is fixed against verticall fnovefnent fe1 ative to the Whee1 and ade assembly, the orm 2|, Which iS anchofed fo the fourna1 beafing thfough the fnedium of the shaft 22, aTfn 26, pfn

27 and strut member 22, sefve to suppoft the outef end of the bfoke caTffer in fts bfake feleaSing posftion, the spring 25 pfoviding 8 fe sflienf lost fnotfon connection betvfeen the arn1 2l and the caffier fof peffnftting relotfve move nlent betvveen the cofffef and ofn1 in (f f(cting either fhe appHcation of the felease of the bfakes as Win hefeInafter n1ofe fully appeaf. It should here be fnentioned thaf the poftion of the Weight of the bfanke figging Whfch fS tTonsnfftfed to the outer ends of the brake carfief ls is insuoient to compreSs the spffng 25 ond thefefofe the spring vvin ff1fntinthe oaffief in fts nornfal release poSftion in which posftfon the aSSociated bfake Shoes 8Jre out of contact vdth the bfake dfum.

ASuning the truok to be 1fghtly 1ooded os is the oojie vhef1 the vefffole is en1pty the Sevefa1 pafts of the fruok and bfake fneohanfsn Win be in the posftfon n Wch they ore shown in g. 2. Novv When the load on the f is increased,

the t ffofne vvf1 move doWnWordly elotive to the Whee1 ond axle ssembly ond oompfess tho tfuok suppofffng Spffng 2. T1e innef of pivote(f end of the bfake oarfief l ond the shoft 22 of the bfoke cofffer adJusting fnechonfsff1 Win move doWnWardly Wfth the tfuok ffone, and os the shaft is thus fnoved, the stfut nen1bef 22, actfng through the medfum of the pfn 22 and arm 2G oauses the shaff 22 and thefeby the afn1 2l to fock in a, oountero1ockWfse dffectfon. This afm 2l os ft fs thus ootuoted, oots thfough the fnedfufn of the feleose spring 2! to fffove the outer end of the bfoke cafnef upWafdly about fts pfvot pfn l2 8 sufffofent dfstonoe to pfevent the doWn ofd n1ovenfent of the pfvoted end of the cofrief ffon1 oousing the bfake shoes 5 to engage the brakedfums |2.

1,ffe anns 26 ond 2l are so propoftfoned thof thfs upvvofd fffovefnent of the outef end of the ooff,fef vvin substontiolly offset of oofnpensote for the doWnWard novenent of the pfvoted end of the oafrfer so os to n1ainfafff the broke shoes spaced oWay ffom the bfaking surfaces of the brake d1ms 8 distance substannan the same os shown in E fg. 2. It Wn1 hefe be noted that the distanoe betWeen the pfvot pfn IT fof the bfke shoes 5 and the pfvot pin l2 for the bfoke cofffef fs suoh that When the outer end of the coffier is odJusted to oonlpensote for the doWnvvofd fnovenlent of the fnnef of pfvofed end, the bfake shoes !5 nfay ossufne o posffion of ol slfght ongle to the ffght of the posftion fn Whfoh they ore shoWn fn fg. 2 but this change fn positfon Wi11 be neglfgfble. fn foct this ohonge nloy be so s1fght thof fof an pfoctfcal purposeS the bfake shoe lf, Inay be oonsfdered as fefnafnJng ff1 Subsfontfolly fhe safne posftfon vfth felation to the brake dfum as they ofe shoWn fn` g. 2. Ffon1 this ft vvfn be oppafent thot When the bfake cofffef is befng adjusted the brake shoes l2 and vvf11 also fefnoin fn substantfany the safne posftfon in Whfoh they are shoWn fn g. 2.

From the foregoing desofiption it Win be seen thaf vvhen thefe is felative fnovemenf betvveen the truck frame and the Wheel and axle assembly thof the bfake o8Tffef ls vvil1 be autofn8tf cally djusted so thot the brake shoes l2, and l Wf11 fefflain fn substontiony their origina1 posfffon.

vvhen ft fs desfred to effect an appHcotfon of the bfakes, ffoid undef pfessure fs adfnftteo fn the usual InanneT t() the bToke cylinder device 2G. In fesponse to the pfessufe of ffuid thus adfffffted. the bfake oyHnder device functfons to aotuote the bfoke oy1indef lever 2 ossoofoted thefevvfth and thefeby the adjacent hangef levef to cause the broke shoes l2 and lf to frictfon s11y engoge the perfpheTal bfoking surf8ces of the bfoke dfums l2. wfth these brake shoes in such engagemenf the fncreosing force befng o pHed to the bfoke shoes thfough the operation of the brake oylfnder devioes oauses the shoes to fnove doWnWardly aong the peripher sl1fces of the drum. the doWnWofdly difected force, due to such ootion, befng tronsfnftted throuEh the bfake cy1fnder lever 22, the hongers 22 and the hanger levef 22 to the brke carrier lo causing the corffer to fnove dovvflvvafdly obout the pin l2 ond ogBfnst the opposfng aotfon of the soffng 25 untn such thne as -the brake shoes ls engage the dun1s. At this time doWnWd movement of 

